SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'daa68b98fed09de03881fdefa076d308b94c62518b670bea2bf109bf74e3d877' 
  AND token = '/aavt1WFqvNDvwCm9tCjyB+SvwYEhcR9OhpykdoJFoY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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