SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b0d923d44184d98b492b66c9fbdc56c7ee0d7df3ec881d71d661783ce2fc0b5a' 
  AND token = '3X1o/1DNiMPljuowhQEt8rYDRxhdChNkyZtxowhYYjU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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