SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6fb3ac2241cda07d69e04fd35b8d3a579d234a51940860a8206cdefffd581e9f' 
  AND token = 'uqVquE/DQBuIXUWdLhZpRk4ZwtgErrAxzojZ4X+MjZw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00008

JSON explain

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