SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '896c729e818e9d73a414f93a53781e088d65f20cf6d426cb947c671604c5a632' 
  AND token = 'n/3FhipcEeczLQWReFXigQ8L//fh8OZaLYCZUlAzie8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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