SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '2620e1943156985c9a8fd8c76a73169bd749a274e8921eb0a01ad83092315c80' 
  AND token = 'DqMMCag4hxRX3cbj4+Oz96TEkyNrlDGIPxMPUmgWUKc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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