SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ad0cf8553ece6f3fbade7f29a93b4116b51c7cee752a53d00551ba79ca1ccc01' 
  AND token = 'tbv6hpBec4OQuApWaKZ/D4zrH0JbfmprhTXskK5AsiY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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