SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '12f69714a1ee096602bc83a18b6604fd9a529473405456df57708df340d0730e' 
  AND token = 'yaHLBAVSwczE/pwpTEghV+H6xWnXDVh5ci4jDbmUdUo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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