SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3ba1e14574ecc888511d27bcffd6d2458073c5341bead047316a06cec0528b36' 
  AND token = '7d5Z8Au+QnU0t2euXXnjCoTpI90upaMMQf5DVfFI01I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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