SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e063fda2600b0ef97b2865e2a0c7b63b974f8fdb5ec29e1ff1d9fb20f6388cc5' 
  AND token = 'tWXItmRJ3vn7Fz/Y4DmYT1Vmp/GbMgHtznGMZfTSjW4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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