SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1c32cc18220d13e4961a439a8be731a7f9fe6e3d0aa4503b74733df04716742e' 
  AND token = 'kYdfqG3RnS91ARfr3eGJ4wZtTiMvqRRE/aGerWBgJf8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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