SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '76732c20474769e5f0fa7b699ee908eddad2f50e193f7ea91eb0ebfacd37353a' 
  AND token = 'kmSGWsOi66DAyAgI6YY74ySCnumcMAWts9yVfAjVKUU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00093

JSON explain

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