SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e8c791124a2b37eaac813666c622f78707d8a4cb455c2f31741adab328ed6785' 
  AND token = 'Wa3HRdEeSr/Wg8v+kz5rQxYkf/MwXfHhDRaPZevCF9U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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