SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '92e4b76301db734c576537a753e2c5d1b399ad6df37d4e1204c7c96abae142a6' 
  AND token = '6SI2yfocTxYTgTzBTVzfhUq4uIHNcofuPX5AVJS/9UA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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