SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '19fd55383cb47d6ee106fe0e16ba1484b32427a76ab95cf4a350f614c4992ef8' 
  AND token = '4A/fyGSZYcek5U51pplRmHONwgXQ+uPEDthahLCeYPU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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