SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '45f5f5aca25283b7399dcec837b106dec51991a3be06198a6bbad3ebc7ead32a' 
  AND token = 'TGBI5b3WGHR0WTldvD8TJ5pDDy/xNdf0k3i+wz42zGU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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