SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'eac4185f1b110b07dc0992b5d4d33eaa63cdfef36edff4e61080c252c1d75dd5' 
  AND token = 'CmqSKk+PFd8nHpzvu9lKSpKTBTH7nXKuxk3CLIL/pZE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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