SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0012a82e0748618cb6acb77e33f2db76246af87e768a41fb7ce152b147d708c0' 
  AND token = 'Yw7d7HIvvy69/EhjUCmwfGL6ZQVLs3lZCqjXnnzo1Kk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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