SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'deff0c45016050f99e56ce7b7d7507f50c04e45bfc0267ea52b14acf74bf15b1' 
  AND token = 'k+xlAcvCGQspbd3Yf+zhYAQRnPQgjZk4gYqgBRaHvcE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}