SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7f6c4f45c93057a30495c01b26faeb63d5c32614a5484533fd29c2445a796bed' 
  AND token = 'N17lVTW7hGmw/CWnmfduZTilXz63XNczRy2KrYCx9Ko=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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