SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6ea59eb9222e03c1effed7c597ebed67fce775236bbf606ecb39464445ad3527' 
  AND token = 'pFhYbXnbOCADzOY0q1dNfgKl3OltSfrTGllpgMnbSNM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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