SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0775f883762bfc93be2a99d569a934a4101aab3aefd60acbf601eef19d682134' 
  AND token = 'tiXaY09CyTTjjplA+tiyBnScpoDRq6jtPJxrz0zjvQ8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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