SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f15918355736543268beca5bba527b9de886450cb3bfbe92ab9359282be52a77' 
  AND token = 'jG/hJhh1kVEbvz13jCZBbgKSu3Vo9PA8Cpw0T+EpgTY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00009

JSON explain

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