SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6e6e87199c8ca7146227ab7f84acd291299a56a6c2b3683c5ee16d7429ad5f57' 
  AND token = 'ki7opFJR5QGpYJAEIBg2j+FZDOcLKBDH2yernTfnR4U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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