SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '672a3e6191c46c1b2fc043e79849a5968e54e5bc7ed71cb2dd36ea1b2ac58100' 
  AND token = 'Tr99KT/2VMXCJSbFfwF/leic7/iGDOFTcGlXb6PtGHk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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