SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'd57b5c90b046aab7e20f56979789d43a92650ba10d79e3bea38de7add4e13cd6' 
  AND token = 'cym7i9903lmFD4oXWYOIwijn8732lZqs8MrmxpFmP3o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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