SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '956f8c16679ffcd18db389aebd845e852a04a889e3a73401f374294580a94ae3' 
  AND token = 'FQZT0YM+kVXESfoVmzO2ufGuvqgXzMDU4XJBOLiGtOA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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