SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7001912b06a84b165c1b7483731879256a9710de8992233a24555057545a967d' 
  AND token = 'U4Jgf3LwdTGhDnimZq6bCXzffPFjizwYTryfnv+kEp8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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