SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '637a58c2a03452d34e9294722d27233d1c51885792a9acdaba9d4ec165da58c9' 
  AND token = 'KLMPoZc9VMWRoSwfkS42ySBEnCScVTbeIrLoRe1mAN8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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