SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f9031097aae9360a6389dbc689211196b3c72dde5e97f43652c644a7fd1f0983' 
  AND token = '/yMstLHIuOyW6gq8tBQIJME42/BEHDiFNX8SalaUgro=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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