SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4a971cd446f55ddb1a69df3ccc43535ddd92f9e9ef5f094c9ba3293f9f3ab1eb' 
  AND token = 'RFrqVDAiZzJzWpfLm/UsaBmeMphcFI9E+bOjdDTuFes=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00056

JSON explain

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