SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd6ece140ecbffb0dadd595adac812b909f0a09ae5e5a57c78bb2ad5dd63fb38c' 
  AND token = 'ONJO9wIjHZ4UBx1SGUm7G1JdMYfLtci57XtkhetTLls=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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