SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7a8f168ba47d255ab04c22d902c3d1d4286fbe7fa5f8a13677337e96f89cfa0d' 
  AND token = 'm5DvbW7JyQI4HwYTztf+JfCuUZP6sizbqsOkbQ+n9UA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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