SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5096003eac790a87479a8afbd7fc075893a2236781de3eadbdc3c0fc1846fa27' 
  AND token = '3e3kNcyHaJx1MXoKHFGmI/CaTymbUmToHdcMBxN3J5Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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