SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '262c26f30fc5b60b81571c89c9681d0bda0d0ce9d0a2803cacfc9d085cd84f85' 
  AND token = 'asazAhC6+wSSEql633H0KEtZgO7KV+jTIDRXvdnff44=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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