SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '596ea070a4c805a18ceef010e9d3a916ac86bac8845d644b9f7ddcc99a49a334' 
  AND token = 'QMDqRc48eZhCGogRhqp0TvDvZSqsrtge5leVMQyIl3s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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