SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '53824df9a0b661388becb3db65bb193467a77552ea394ec9e22e1055a85b0a56' 
  AND token = 'WedTa+VpIBpGBbyYpt9ObVsFyBPvDccoCf4OB9Cw8R0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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