SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0143c866d236a1db9517ed6db8271b6212b9a7b3fc8fd0618204dc4b62cc3312' 
  AND token = 'dc0r2bSI0jJZJsuwp368XZe2OnDA5/DCQDkVBiWUycM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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