SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9c74f5be12f2724addf39168c28375016bbcb529a18595534f3ed6fdf9b348d7' 
  AND token = 'picZjGvWCvxo2LzDHdUj9w8gRX8V/jnAwRJfYTpR8wg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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