SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0c875252fb913598f8c6537e68d0040d8b38c9e60127e9f83e6eba7e405e3024' 
  AND token = 'AMXK2K1v0ERZqRqtfJPUJOE4gJ/lGwe8+TbHzQG01NU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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