SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e41661673dfe03960977c7db93cbcdd8b8638444bb015fe4f3be6a88a7fa655e' 
  AND token = 'c2ozKBZlnsf8cpyD4n2gQ/tCSo9Zo2afVFQRnNurqMo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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