SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '728900903984a71859967ea8bd5472a4ad2b1896b300d222efdc908ffbff8f30' 
  AND token = '2/cuMBfxtspBNLQhMcXQHC24hgEO9RT0xK/Y/JrW/p4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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