SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8f455106ebc0951e54919887234e40ec40b252f30e699b35547cec613bf4a683' 
  AND token = 'FV/XXLKmgPvZNodQnbY7CGmamqIuRMGBz66vrVu8EN0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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