SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd2a2c822e0e33189826c153c75c0f00c5a088bccc83e6262a316a0160a41c641' 
  AND token = '1oPQzpMEj6xHmhafVbQrVV+u5YV3gQGUFuN1jz+wgJI=' 
  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"
    }
  }
}