SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b431592cc941d9c66afe17d5450e413a82fe30a74619dcfd6c805ef9f3724bc1' 
  AND token = 'g5hR7QRccF2QlUrVrX2QdRY6ithlymbdqLc4UUzNIT8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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