SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c29cd0b176d9810f9a1cfdc1ac2c8318022dbf7322a3257cbdbb371a1bc648cb' 
  AND token = 'xhe5BUo4GY7M5IhptRIufHZ5+tsKp4sPHwiXwt7P5P0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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