SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0fa651cddd88f6b3a4c2968f9caf3c37401621c5c406bada58a741b16d1cfb2f' 
  AND token = 'O8VndCtjvbncECWX1pKol1qflqml/ORP7I7+NntkwPI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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