SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'af05df4b2d304f1b46f46956c5d2aa980594bda92b18670229360f1853732ca2' 
  AND token = 'B888SpHGFLRGwNBPq7ChqDzoXrdRf8QXPiTkxKVFJBQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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