SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3434e1fe2b22139f286f50696b0b94d150efd65e0e6fea578e30e109f46a4277' 
  AND token = 'Uixao25cRXhV3ajefdrOlBcmIBG8bT/6oyp0JsMqniM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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