SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd871685a89212fd888edbc43c6f21881cd4395200724311054bb8d329de50805' 
  AND token = 'myUQyOXWTGG+JkO3179xAy12URROnT7qE1Xy3sdGLUw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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