SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '64a300a076c8b2d84d82d676ced819bede50d31608af727297291125270f7ddd' 
  AND token = 'OhU3B6jgWAEPxUmtIcMxpEDRCgaWi4+sRc3gE44QN1g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00052

JSON explain

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