SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1c25bf1b458a4792ee0891c2f402858c4a10a7ce4eb9dc86843375c1490d0e6c' 
  AND token = '9nGKNhsjbeCCRQ7zYulInoyUeWtD1lBbmqcfvHjKm+A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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