SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '243020951d57a64d99edaa540540878faf5db0e5cd249f7e08c96446373c2635' 
  AND token = 'As+/wCfTGsCUyGAFeyhGJZRvgA3g5/3vzSTJB0OEs8E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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