SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e4b48509dfab09f15e4f83cb2257103d1bedc3c2ab2b113c9a18eb985e196fb9' 
  AND token = 'ZnB6UV54sfAKtie5t8AwqXvU/PFLcK22NGmtYSej0bQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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