SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '46b90ca37aaac84dda85cf7369fb7de7f60845f519708b9694879652d2a8dbe2' 
  AND token = '/lT+b5WSNHEvqn3gzYsw/120pDgcePPf81n4yCt/dAU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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