SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8e832854ccb31103d55bb6719454f127d02e814e96f33301eb78bec9f2f70d8a' 
  AND token = 'spID8ZjFF886kpH+XdeecuhYhzOtcMqQZb+eNpLCNhg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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