SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '61fef3e0355177e1737ba217e5bde5e5fc1cb35f19193834b45fc061ffe4b308' 
  AND token = 'UsXsgReLkYBktBgG+pombsWX1emS0X8MpIwxRmyEVFE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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