SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'e8c208a65c72087bce5725bec399404bd46a15b70387dc84d72672768ab080dc' 
  AND token = 'r38NhI7q6SehwJgCiOGXKLJynxtwdx9+xMI7HQrFQIM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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