SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1a9fdd93488588e3c1ada91bd1d52885b100cf78716190a60d5c930a85ad7d51' 
  AND token = 'X6tg8QdJ5k/Cjyclbv0iNSLMYMk6SV1P3vDsKP9cUK0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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