SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a320561414382c519258df91bdb661d8daf50f8f7a6e224f7da66d8d8b60ca01' 
  AND token = 'tWN/8recbp56nXjCMKAgj8Yja5RHzVs7UC8+0oPNsgI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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