SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6c7c81d11d04e809eca2cbac579478008da8e9925e44fb9bc45706e0fa8cb6e0' 
  AND token = 'wFXzLpv4bRfEMyRDNd6G6QR1X8wtAthS4xKkFCyd5c8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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