SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f1038a51dec9ae4ce9d7b7becd9aa245970ad36974e70b0d9edbcae891c91bcf' 
  AND token = 'PPCy02AtRh+vNnRYxFLWEGPmBDk4VFlhXwRqP75FBLc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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