SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '004d439f8ed278dd16c9dd0c2ea6f07e8c19278b848dae90b0b957cea9e48862' 
  AND token = 'WS45Ge5Nf1qT2tVYGET1q7YxdSXo4BxaIF7NRUfEWOE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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