SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7c61d197633ea3121dbbb7444a457193b1b267aadfbbc72b8e5279fad1f5ac6d' 
  AND token = 'JLw3+pXZSVMMGi2SWKzaPf1JJYTqh6JIneJkEBq8DUg=' 
  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"
    }
  }
}