Sandbox

SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '339e1f9ca52100c9de02f7b7e09895dee78fd64a035d9d8c0403d031389a5e67' 
  AND token = '5yf30VbsZNbi6SdOKHaf5ztjnuacCXIiMUayMQN6sa8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00012

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}