SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e53e1d9248ec10ed76a84541483a40bd2b16898d130c5080ba8c9656129138fa' 
  AND token = 'MYaHCDW3EwPWVTag4CHShem7Du2pp9/JZDhvFvDTngY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}